Feature request: implement Gimphash calculation

[Neo23x0]

https://github.com/NextronSystems/gimphash

[stevemk14ebr]

I've been meaning to evaluate this computation for a while now. It's something I'd like to include for sure. Though some concerns I need to vet personally first before I implement this:

• How stable is it per compilation of the same source/compiler, what about including changes to source, what breaks it?
• How stable is it across go versions? The runtime has evolved significantly over time, should there be a cutoff version, a generic version, or a different computation per version?
• Do other rules need to be included? It's not clear to me if ignoring internal/ is the best as many go applications include real application logic under internal paths. Similarly with vendor, it may be useful to include that, what are the tradeoffs there?
• • Are the standard library exclusions listed complete, go. and type. intuitively seem to make sense off hand, are there others? Have they changed over time?

I do plan on looking into these, if you have any insight it would help move this along.